Electrically-operated fuel pump for internal-combustion engines



March 25, 1930.

ELECTRICALLY w. c. CARTER 1,751,9'2'5 OPERATED FUEL PUMP FDR INTERNALCOMBUSTION ENGINES Filed July 24, 1924 All! - IN VENTOE MUN/am CC'Qrfer.

Patented Mar. 25, 1930 UNITED STATES PATENT OFFICE WILLIAM C. CARTER, OFFLINT, MICHIGAN Application filed July 24,

This invention relates to devices of the kind that are used for pumpinga liquid from a lower to a higher level, and has for its main object toprovide an electrically-operated pump, which, in addition to having agreat pumping capacity, is reliable in operation, inexpensive toconstruct, economical in the consumption of electric current and of suchdesign that the contacts will be separated with a quick break, therebytending to prevent the current from arcing and burning the contacts orrendering them defective.

Another object is to provide a highly efficient and compactelectrically-operated fuel 35 pumping apparatus for internal combustionengines in which the electrically-operated means that actuates thepumping element is of novel construction and is so designed that theelectric circuit from which said means receives its source of power willbe opened automatically after the fuel in the reservoir rises to acertain predetermined level and will remain open so long as the fuel insaid reservoir stands above said predetermined level. Other objects anddesirable features of my invention will be hereinafter pointed out.

\Vhile I have herein illustrated my invention embodied in a liquid fuelsupplying apparatus for internal combustion engines that is particularlyadapted for use on power-operatcd vehicles for pumping gasolene from asupply tank into a relatively small feed reservoir that may either formpart of a carburetor or from which fuel is conducted to the floatchamber of a carburetor, I wish it to be understood that my invention isapplicable to various other kinds of apparatus that are used for pumpingliquid from a lower to a higher level.

Figure l of the drawings is a vertical sectional view of an apparatusconstructed in accordance with my invention, taken on the line 22 ofFigure 2; and

Figure 2 is an end view of the apparatus on a reduced scale, showing thecover or cap piece of the intermittent switch removed and a portion ofthe feed reservoir broken away so as to show the outlet from same.

Referring to the drawings which illustrate 5 the preferred form of myinvention, A desig- 1924. Serial No. 728,051.

nates the pumping element of the apparatus which consists of a memberthat is adapted to be moved in one direction so as to suck liquid fuelinto a pumping chamber 1 from a supply pipe 2, and thereafter moved inthe opposite direction so as to force the fuel out of the chamber 1 intoa feed reservoir B that is equipped with an automatic inlet valve 3 thatis normally held seated by a spring 4 which is strong enough to preventthe valve 3 from opening in the event the fuel tank (not shown) fromwhich the supply pipe 2 leads becomes arranged at a higher level thanthe feed reservoir 13. The inlet valve 3 of the feed reservoir B alsoconstitutes the discharge valve of the pumping chamber 1, and saidpumping chamber is also equipped with an automatically-opcrating inletvalve, preferably a ball check valve 5, arranged between the supply pipe2 and the pumping chamber 1, as shown in Figure l. The feed reservoir Bmay either form part of a carburetor, or it may be used for supplyingliquid fuel to the float chamber of a carburetor, the reservoir B of theapparatus herein illustrated being pro vided with a discharge opening 6,as shown in Figure 2, from which the fuel escapes from said reservoir.The pumping element A may consist of a reciprocating plunger, or avibrating member, such as a diaphragm, it being preferable to use adiaphragm composed of a number of disk-shaped pieces of treated fabricarranged so as to form one wall of the pumping chamber 1 and havingtheir peripheral edge portions secured by a clamp 7 i to a member 8 inwhich the pumping chamber 1 is formed, said member 8 preferablyconsisting of a casting that carries the valves 3 and 5,'the feedreservoir B and the electrically-operated mechanism that actuates thepumping element A.

The electrically-operated mechanism just referred to consists of asolenoid that comprises a coil C and a core composed of a movable memberD and a stationary member D. In the form of my invention hereinillustrated the solenoid is intended to be operated by direct current,but in view of the fact that the core pieces of the solenoid pulltogether, regardless of the direction of flow of the curmember D isrigidly connected to the pumping element A preferably by a screw thatpasses through a pair of metal plates 11 that embrace the centralportion of the diaphragm that constitutes the pumping element A. Thecoil C of the solenoid is surrounded by a metal housing E of magneticmaterial that bears against the part 7 and which is detachably connectedby screws or other suitable fastening devices 12 to the member 8 inwhich the pumping chamber 1 isformed, said part 7 also being of magneticmaterial. A. sleeve 13, preferably formed of brass, is arranged insideof the coil C so as to serve as a bearing or slideway for an annularfibre member-14 that surrounds the movable member D of the core of thesolenoid. By constructing the solenoid in this way I insure the movablemember D of the core being maintained in properly spaced relation withthe coil and moving freely relatively to same without the use of alubricant, as the annular fibre piece 14 that surrounds the movable partD of the core does not require a lubricant to make it slide freelyinside of the brass sleeve 13. 'While I prefer to contruct the solenoidin the manner above described, it is not absolutely essential that themovable element of the solenoid be supported and guided in thisparticular way.

The electric circuit that is used to energize said solenoid is providedwith two switches, one a manually-operated switch (not shown) that isclosed when the apparatus is in use,

and the other an automatically-operating, intermittent switch that opensand closes said circuit intermittently so as to cause the movable'memberof the core to reciprocate, and thus actuate the pumping element A. Theintermittentswitch just referred to is arranged inside of a removablecap piece or cover E on the end wall of the housing E and comprises astationary contact 15 and a movable contact 16. The cover E may beformed either of magnetic or non-magnetic material. The stationarycontact 15 is car ried by a member 15 that is secured to the end wall ofthe housing E and insulated from same, which member 15 is electricallyconnected with one end of the coil C of the sole noid, as shown inFigure 2. The movable contact 16 is carried by a movable member 16herein illustrated as'a lever that is pivotally connected at one end bya pin 17 to ears 18 on the end wall of the housing E, said lever beingadapted to be moved towards and away from the stationary contactcarrying member 15*- and being provided at its lower end with anangularly-disposed arm or extension 19 that limits the movement of thecontact 16 when said lever is moved to break the circuit. In order toinsure a good electrical connection between the lever 16 and thehousingE, which is grounded, said lever is electrically connected by a piece ofwire 20, commonly referred to as a pig tail to the end wall of thehousing or to some other suit ablegrounded member.

The means that I prefer to use for separating the contacts 15 and 16 tobreak the circuit that energizes the solenoid consists of a hammer F ofmagnetic material, arranged so that it will impart a sharp blow to thelever 16 on which themovable contact 16 is mounted at or about the timethe movable member D of the core of the solenoid reaches the end of itsinward stroke. During the inward stroke offs-aid member D energy isstored in a spring 21, due to the movement imparted to the hammer F inone direction by magnetic force, and when the movable member D of thecore comes in contact with the stationary member D, the hammer F movesin the reverse direction under the influence of the spring 21 andstrikes the lever 16 a blow in a direction to cause the contacts 15 and16 to in Figure 1, the hammer F is formed by a tubular member that isreciprocatingly mounted inside of a sleeve 22 of non-magnetic material,preferably brass, said hammer being arranged so that the outer end ofsame bears against the inner side of the lever 16. Said hammer and lever16 are connected together by the spring 21, previously referred to,which is a contractile spring connected at one end to the lever 16 andat its opposite end to the tubular hammer F inside of which said springis arranged, the spring 21 being herein illustrated as connected to thehammer F by solder 23. The brass sleeve 22, inside of rection to closethe circuit in which the contacts 15 and 16 are arranged consists of arod 25 attached at its inner end to the movable member D of the core ofthe solenoid and having its outer end projecting through a hole in thelever 16 and threaded so as to receive an adjustable stop 26 that isarranged on the outside of the lever 16, said stop being adapted to bearagainst the lever 16 and move it towards the stationary contact carryingmember 15 when the movable member D of the core of the solenoid reachesthe end of its outward stroke. If the circuit of the solenoid is closedwhen the parts of the intermittent switch are in the position shown inFigure 1, the member D of the core of the solenoid will move inwardlytowards the stationary member. D of said core and the hammer F will moveinwardly towards the center of attraction, due to the magnetic forceproduced by the-current flowing through the coil 1 5 C of the solenoid,the path of the magneticfiuxbeing from D to D and through the housing Eand part 7 back to the core piece D. In view of the fact that the hammerF is arranged inside of the core piece D, the

flux will also flow through said hammer, 'thence through the plate 24,thence through only holds the contacts 15 and 16 tightly together, dueto the pull which the spring 21 exerts on the lever 16*, but it alsobuilds up energy in the spring 21 by increasing the tension of same.

As soon as the circuit is opened or interrupted by the blow imparted tothe lever 16 by the hammer F, the movable member D of the core of thesolenoid moves outwardly underthe influence of the spring 9 which wasplaced under tension by the inward stroke of said member D. 'During thisoutward movement of the member D the circuit is held open by thecramping action of the hammer F on the lever 16 due to the change inangularity of said lever and hammer. When the contacts 15 and 16 areclosed, the lever 16* will be arranged at right angles to thelongitudinal axis of the hammer F, thereby causing the flange 27 on theouter end of said hammer to bear squarely against the inner side of saidlever. When, however, the hammer F strikes thelever 16 a blow, saidlever swings into an inclined position, wherein the inner face of saidlever is disposed at a sulficiently sharp angle to the end face of theflange 27 on the hammer to cause the lower edge of said flange to bearagainst the lever 16 and hold it in the slightly inclined position intowhich it was moved by the blow of,

the hammer, it being remembered that the hammer and lever 16 areconnected together by the tension spring 21. When the movable member Dof the core of the solenoid reaches the end of its outward stroke, thestop 26 on the rod 25, that is attached to said member engages the lever16 just before the member 1) reaches the end of its outward stroke, andthus causesthe lever 16 to swing back to its former position in parallelrelation with the flange or head piece 27 on the end of the hair.- merF, thereby causing the circuit to be closed automatically as soon as thecontact 16 engages the contact 15. Immediately thereafter the movablemember D of the core and the hammer F will move inwardly towards thecenter of attraction, as previously described. If desired, a compressionspring 21 can be arranged at the inner end of the hammer F in such amanner that energy will be stored up in said spring 21* by the inwardmovement of the hammer F and the movable member D of the core, it beingpossible to design the spring 21 so that it will assist in the operationof moving the hammer F outwardly.

From the foregoing it will be seen that in my improved pumping apparatusthe hammer F, which is reciprocatingly mounted inside of the stationarymember D of the core, is reciprocated or moved in opposite directions bythemagnetic force of the solenoid. \Vhen the coil of the solenoid isenergized, the hammer is attracted, with the result that the hammer willmove inwardly towards the movable member of the core, which is in thesame circuit as the hammer F. When the movable member of the corestrikes against the stationary member, and thus closes the air gap, thenthe power of attraction of the magnet becomes greatest at the outer endsof the core pieces, with the result that the hammer will be subjected toa force tending to move it outwardly or towards the lever 16. During theinward movement of the hammer energy is stored in the spring 21, andwhen the movable member D of the core comes in contact with thestationary member D, said spring 21 causes the hammer to move outwardlyand impart a sudden blow to the lever 16, thereby causing the contacts15 and 16 to be separated with a quick break.

In a structure of the kind above described the magnetic force producedin the solenoid is used for the two-fold purpose of holding the contactsclosed during the stroke of the core in one direction, and to effect theseparation of the contacts with a quick break at the end of the saidstroke of said core. While the construction above described is what Iprefer to use, I do not wish it to be understood that my invention islimited to an apparatus of the particular construction hereinillustrated, and instead of using the electric current flowing throughthe coil of the solenoid to hold the contacts closed and use a spring toseparate said contacts, the apparatus might be constructed in such a waythat the contacts will be held closed by a spring and opened -by themovement imparted to a member by the electric current flowing throughthe coil of the solenoid.

The feeding reservoir B is provided with a float G that is used foractuating a'mechanism which causes the pumping element A toautomatically cease o crating after a certain quantity of fuel has eenpumped into said reservoir and to remain inactive for a certain period,for example, until the reservoir is -nearly empty, or so long as thelevel of the fuel in said reservoir remains above a certain point. Themechanism ust referred to comprises a member 30 arranged so that whenthe float G in the reservoir B rises to a certain height the position ofthe member 30 will change automatically, and thus cooperate with a rodor other suitable part 31 attached to the movable member D of the coreof the solenoid to arrest the movement of said member D on its outwardstroke before said member D reaches such a position that the stop 26 onthe rod 25 engages and moves the lever 16 in a direction to bring thecontacts 15 and 16 together. In the apparatus herein shown the member 30consists of a rod pivotally mounted adjacent its lower end in thecasting 8 and arranged so that it projects upwardly through a centerhole in the float G, the piv otal connection between said rod 30 andcasting 8 being of suchv a character that said rod can wobble or rock invarious directions. An oscillating member H that is pivotally connectedat 32 to a bearing 32 on the underside of the cover of the feedreservoir B is provided with a roller 33 and two arms 34 and 35 arrangedabove and below the float G, said arms being rigid with the member H, sothat when pressure is exerted on either of 'said arms by the float G,the member H will rock on'its pivot. lVhen the float G moves upwardly,due to a rise in the level of the fuel in the reservoir B, the float Gwill exert pressure on the arm 34 and rock the member H upwardly,thereby causing the roller 33 on said inember to exert pressure againstthe side of the upper end portion of the rod 30 and move the upper endof said rod to the left, looking at Figure 1. This, of course, causesthe rod 30 to assume a slightly inclined position, wherein the lower endportion of said rod is positioned a trifle farther to the right than theposition which the lower end portion of said rod occupies in Figure 1.Assuming that this change in the position of the rod 30 was effected ata time when the movable member D of the core of the solenoid was movingoutwardl the rod or part 31 attached to said member i) will strike thelower end portion of the float-governed member 30 and be arrested bysame before the movable member D of the core of the solenoid moves farenough to move the contacts 15-and 16 of the intermittent switch intoengagement with" each other, with the result that the pumping element Aimmediately ceases operating. So long as the fuel in the reservoir Bremains at such a level that the float Gexerts pressure on the memberI-Iin adirection tending to hold the rod 30 in an inclined position, theenergizing circuit of the solenoid [will remain open and the pumping-eleiiiuent will remain inactive. As soon as the'levelofthefuel in therelieve the" -pr}fessure oaths-member and thus permit the rod 30toassume a vertical.

position, the contacts 15 and 16 of the intermittent switch will close,due, of course, to the fact that the movable element D of the core isthen free to move to the end-of its:

outward stroke, and immediately thereafter the pumping elementAlvwill-start operating,

thereby resuming the pumping of-fuelrinto the reservoir B.- The arm35Eonthe-oscillat-z ing member; II that is arranged :under the float Gis usedto positivelymove the :member- 33 in a direction'to relievethesidewiseypres sure on-the upper end ofthe rod 30 in :the, eventgravity fails to move the member H- downwardlyj when the float G 'movesout of engagement with the arm 34, due'toa drop inv theleveL-of the fuelin the reservoir B. I

30 passes, and at the same time permit said member 30 to rock or wobblefreely, I prefer to support the member 30 by a diaphragm 36 whose inneredgeportion is clamped between collars 37, soldered on the rod 30, andwhose peripheral edge portion is clamped between gaskets 38 that areheld pressed tightly together by an annular-shaped clamping member 39that is screwed into a threaded recess in the bottom of the feedreservoir B.

Assuming that the reservoir B is empty and that the manually-operatedswitch (not shown) in the solenoid circuit is moved into its closedposition, the movable member D of the core of the solenoid and thehammer F will both start to move inwardly towards the center ofattraction as soon as the electric current starts to flow through thecoil C of the solenoid, the inward movement of the member D imparting asuction stroke to the pumping element A, and thus causing a charge offuel to be drawn into the pumping chamber 1 through the supply pipe 2.When the member D of the core engages the stationary memberD themagnetic pull on the hammer member, becomes diminished and the hammer Fimmediately flies outwardly under the influence ofthe spring 21, therebyseparating the contacts 15 and 16 with a quick break, whereupon themovable member'D of the core will move outwardly under the influ'- enceof the spring 9 and impart a power stroke to the pumping element A thatcauses the charge of fuel in the pumping chamber 1 to be forced out ofsame past the valve 3 and into the reservoir B. As the movable member Dof the core of the solenoid nears the end of its outward stroke the stop26 on the rod 25'attachedto said member D engages the lever 16 and movessaid lever in a directhe fuel in the reservoir B drops low enough tionto close the contacts 15 and 16, whereu on current will again flowthrough the coil of the solenoid and cause the movable member D of thecore to move inwardly. The above operations are repeated until the levelof the fuel in the reservoir 13 has risen high enough to cause the floatG to exert sufficient pressure on the oscillating member H to move therod 30 into an inclined position. After said rod 30 has been shiftedinto an inclined position the pumping element A automatically ceasesoperating, due to the fact that the lower end portion of said rod 30co-operating with the part 31 on the movable element D of the solenoidprevents said member D from moving far enough to cause the stop 25 toengage and move the lever 16 in a direction to close the contacts of theintermittent switch. It will thus be seen that when the pumping elementA ceases operating the energizing circuit of the solenoid remains open,and accordingly, no electric current is consumed at such times, namely,when the reservoir B is full or when the float G in said reservoiroccupies such a position that it does not exert pressure on the arm 35of the rockable member H. I-Iowever, when the level of to cause thefloat G to exert pressure on the arm 35, the rod 30 will spring back toits normal vertical position, and immediately thereafter the contacts 15and 16 will close and the movable element D of the solenoid will startreciprocating and cause the pumping operation to be resumed.

IVhile I have herein illustrated my invention embodied in anelectrically-operated pumping apparatus in which the reciprocating coreof a solenoid is connected with a pumping element which said coreactuates, I wish it to be understood that it is immaterial, so far as mybroad idea is concerned, whether the pumping element of the apparatus isformed by an integral portion of the core of a solenoid or by a memberactuated by or operatively connected with the core of a solenoid.Moreover, while I have herein illustrated the circuit-closing device inthe solenoid circuit arranged so that the magnetic force is utilized tohold the contacts closed when the core of the solenoid is moving in onedirection and a spring is used to thereafter close the contacts afterthey have been separated, I wish it to be understood that thecircuit-closing device could be arranged in various other ways withoutdeparting from this feature of my invention, which, broadly stated,consists in using magnetic force produced by electric current flowingthrough acoil to hold contacts in the energizing circuit in onecondition during the stroke or a certain portion of the stroke of thecore of a solenoid, said contacts being subsequently separated to permitthe core to move in the opposite direction, and said contacts beingthereafter closed, preferably by a spring, so as to impart anotherstroke to the core of the solenoid.

Having thus describedmy invention, what I claim as new, and desire tosecure by Letters Patent is: a

1. In an electrically-operated pumping apparatus, a solenoid providedwith a reciproeating core, contacts-in the circuit used to energize thesolenoid, and means for utilizing the magnetic force produced in thesolenoid for holding said contacts closed during the stroke of the coreof the solenoid in one direction, and to effect the separation of saidcontacts with a quick break at the end of the said stroke of said coilf2. In an electrically-operated pumping apparatus, a solenoid providedwith a reciproeating core, contacts in the circuit that energizes thesolenoid, a means operated by the magnetic force in the solenoid forholding said contacts closed during the stroke of the core in onedirection and for separating said contacts with aquick break at the endof said stroke, and a spring for closing said contacts when the coreapproaches the end of its stroke in the opposite direction.

3. In an electrically-operated pumping apparatus, a solenoid providedwith a reciprocating core, contacts in the circuit that energizes thesolenoid, a means operated by the magnetic force in the solenoid forholding said contacts closed during the stroke of the core in onedirection and for separating said contacts with a quick break as thecore nears the end of its said stroke, and an independent means forclosing said contacts when the core nears the end of its stroke in theopposite direction.

4. In an electrically-operated pumping upparatus, a solenoid providedwith a movable core, a circuit-closing device in the energizing circuitof the solenoid, and a hammer for imparting a sharp blow to saidcircuit-closing device arranged so that the magnetic force produced bythe current flowing through the coil of the solenoid causes said hammerto move, first in a direction away from said circuit-closing device, andthereafter in the re- Verse direction into sudden engagement with saidcircuit-closing device.

5. In an electrically-operated pumping apparatus, a solenoid providedwith a movable,

core that is adapted to be moved inwardly by imparting a sudden blow tosaid circuit-clos ing device so as to separate the contacts with a quickbreak.

6. In an electrically-operated pumping apparatus, a solenoid providedwith a movable core, a movable circuit-closing device in the energizingcircuit of the solenoid, a hammer for imparting a sudden blow to saiddevice so as to open the circuit when the core of the solenoid nears theend of its stroke in one direction, and a spring for actuating saidhammer arranged so that the magnetic force produced by the currentflowing through the solenoid causes energy to be stored up in saidspring.

7. 11 an electrically-operated pumping apparatus, a solenoid providedwith a movable core arranged so that it will move in one direction whencurrent flows through the coil of the solenoid, a movablecircuit-closing de vice in the energizing circuit of the solenoid, and aspring-actuated hammer for moving said device in a direction to efiect achange in the condition of the circuit, arranged so that said hammerwill move away from said device towards the center of attraction whencurrent flows through the coil of the solenoid and thereafter will movein the reverse direction under the influence-of its actuating spring andimpart a blow to the circuit-closing device so as to change the positionof same.

8. In an electrically-operated pumping apparatus, a solenoid providedwith a movable core arranged so that it will move in one direction whencurrent flows through the coil of the solenoid, a movablecircuit-closing device in the energizing circuit of the solenoid,

a hammer for moving said circuit-closing de vice into its open position,arranged so that after it has actuated saiddevice it will maintain saiddevice in its open position, and an independent means for moving saidcircuitclosing device into its closed position.

' 9. In an electrically-operated pumping apparatus, a solenoid providedwith a movable core arranged so that it will move in one direction whencurrent flows through the coil of the solenoid, a movablecircuit-closing device in the energizing circuit of the solenoid, ahammer for moving said circuit-closing device in one direction, and aspring that joins said hammer to said device, said hammer being soarranged that it will be moved by magnetic force in a direction to storeup energy in said spring, and u on the core reaching the end of itsstroke 1n said direction, will move in the reverse direction under theinfluence of said spring and impart a blow to said circuit-closingdevice.

10. In an electrically-operated pumping apparatus, a solenoid having acore composed .of a stationary member and a movable memher, the'movablemember of saidcore being adaptedto be .moved inwardly by'the magnetloforce produced by current flowing through the coil of the solenoid, aspring for moving said movable member outwardly, a movablecircuit-closing device in the energizing circuit, a hammer arranged sothat it will be moved by the magnetic force towards the center ofattraction of the coil, a contractile spring attached to said hammer andto said circuit-closing device, said hammer being adapted to be moved ina direction to impart a blow to the circuit-closing device after themagnetic force has been shunted from the hammer to the stationary coremember, thereby causing the energizing circuit to be opened, and a meansrendered operative by the movement of the movable member of the core onits outward stroke for moving said circuit-closing device in a directionto close the circuit.

11. In an electrically-operated pumping apparatus, a solenoid having acore composed of a stationary member and a movable member, a spring forholding the members of said core separated, a pivotally-mountedcircuit-closing device in the energizing circuit of the solenoid, ahammer that bears against one side of said device, a contractile springconnected to said device and to said hammer, said hammer being adaptedto be moved away from said device towards the center of attraction bythe magnetic force produced by current flowing through the coil of thesolenoid, thereby causing said contractile spring to be placed undergreater tension, the engagement of the movable and stationary members ofthe core causing the hammer to be released, whereupon the hammer impartsa blow to the circuit-closing device, and a means operated by themovable member of thecorc for moving said circuit-closing device in adirection to close the circuit when the movable member of the core nearsthe end of its outward stroke.

12. In an electrically-operated pumping apparatus, a solenoid comprisinga coil and a movable core, a metallic sleeve arranged on the inner sideof the coil, a non-metallic means on the core that slides in saidsleeve, and holdsthe core in spaced relation with the coil, and meansfor automatically openingthe circuit that energizes the coil when saidvcore nears the end of its stroke in one direction and for automaticallyclosmg said on- ,cuit when said core nears the end of its stroke closingdevice so as to separate the contacts in the circuit with a quick breakwhen the movable member of the core nears the end of its stroke in onedirection, and means for part on the movable member of the core that Islides in said bearing, an intermittent switch in the energizing circuitof the coil comprising a lever that carries the movable contact of saidcircuit, a reciprocating hammer arranged at the center of the stationarymember of the core and adapted to be moved by magnetic force towards thecenter of attraction when current is flowing through the coil, the outerend of said hammer bearing against the inner side of said lever, acontractile spring connected to said hammer and lever, and a deviceconnected to the movable member of the core and arranged on the oppositeside of said lever for moving the same in a direction to close thecircuit when the movable member of the core nears the end of its outwardstroke.

15. In an electrically-operated pumping apparatus, a solenoid having acore composed of a stationary member and a movable member, a spring thatexerts pressure on the movable member of the core in a direction tendingto hold it spaced away from the stationary member, an intermittentswitch in the circuit that energizes the solenoid coil pro: vided with apivotally-mounted circuit-closiug device, a tubular-shaped hammerreciprocatingly mounted inside of the stationary member of the core andarranged with the outer end of same bearing against said C11-cuit-closing device, a contractile spring con nected to said device andto said hammer, and a compression spring at the inner end of the hammerarranged so that it will be placed un der compression by the inwardmovement of the movable member of the core.

WILLIAM G. CARTER.

